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A fifth democratic challenger has officially entered the race for 2020. Julián Castro launched his bid for the White House on Saturday, becoming the first Latino candidate in an increasingly crowded field. The 44-year-old Castro previously served as secretary of housing and urban development in the Obama administration.

“When my grandmother got here almost 100 years ago, I’m sure she never could have imagined that just two generations later… [I’d say] these words: I am a candidate for president of the United States of America,” Castro declared during his rally at Plaza Guadalupe in San Antonio, Texas. He had previously released a video announcing his exploratory committee in December.

Castro becomes the fifth Democrat candidate to make a formal announcement for their 2020 bid, following Hawaii congresswoman Tulsi Gabbard, West Virginia state senator Richard Ojeda, Maryland congressman John Delaney and entrepreneur Andrew Yang. Massachusetts senator Elizabeth Warren has also confirmed an exploratory committee for her own 2020 presidential campaign as well.

Recently, Castro gave an interview with ABC’s George Stephanopoulos calling for investments in education, universal higher education and Medicare for All. His announcement speech also covered the need to address climate change, and the issue of border security. “Yes, we must have border security, but there is a smart and humane way to do it,” said Castro, whose grandmother was born in Mexico. “And there is no way in hell that caging children is keeping us safe.”

Castro was the youngest person elected to San Antonio City Council in 2001, and later became the youngest in the Obama cabinet at age 39. He was elected San Antonio’s mayor in 2009, delivered the keynote address at the 2012 Democratic National Convention, and made the short list of candidates for Hillary Clinton’s running mate in 2016. Julián is also twin brother to democratic Rep. Joaquin Castro, who chairs the Congressional Hispanic Caucus and is expected to be involved in his campaign.